Precision Measurement of the Beam-Normal Single-Spin Asymmetry in Forward-Angle Elastic Electron-Proton Scattering.

A beam-normal single-spin asymmetry generated in the scattering of transversely polarized electrons from unpolarized nucleons is an observable related to the imaginary part of the two-photon exchange process. We report a 2% precision measurement of the beam-normal single-spin asymmetry in elastic electron-proton scattering with a mean scattering angle of θ_{lab}=7.9° and a mean energy of 1.149 GeV. The asymmetry result is B_{n}=-5.194±0.067(stat)±0.082 (syst) ppm. This is the most precise measurement of this quantity available to date and therefore provides a stringent test of two-photon exchange models at far-forward scattering angles (θ_{lab}→0) where they should be most reliable.

Major histocompatibility complex class II+B7-1+ tumor cells are potent vaccines for stimulating tumor rejection in tumor-bearing mice.

Mice carrying large established major histocompatibility complex (MHC) class 1+ sarcoma tumors can be successfully treated by immunization with genetically engineered sarcoma cells transfected with syngeneic MHC class II plus B7-1 genes. This approach is significantly more effective than previously described strategies using cytokine- or B7-transduced tumor cells which are only effective against smaller tumor loads, and which cannot mediate regression of longer-term established tumors. The most efficient tumor rejection occurs if both the class II and B7-1 molecules are coexpressed on the same tumor cell. Immunity induced by immunization with class II+B7-1(+)-transfected sarcoma cells involves CD4+ and CD8+ T cells, suggesting that the increased effectiveness of the transfectants is due to their ability to activate both of these T cell populations.

Hemoglobin Portland 1: a new human hemoglobin unique in structure.

A new hemoglobin (Hb), Portland 1, has been found in a newborn infant having multiple congenital anomalies and complex autosomal chromosomal mosaicism. The new hemoglobin has a unique tetrameric structure (molecular weight, 66,000) composed of two pairs of different types of chains, neither of which is alpha, gamma(2)x(2). The x-chain of Hb Portland 1 may be a new type of hemoglobin chain, but the available evidence suggests that it may be identical with the epsilon chain. We suggest that Hb Portland 1 is an embryonic hemoglobin that persisted until after birth in relatively large amounts in this patient.

Hemoglobin Freiburg: abnormal hemoglobin due to deletion of a single amino acid residue.

Structural characterization of a new variant of human hemoglobin (adult), designated hemoglobin Freiburg, indicates the deletion of the valyl residue No. 23 from an otherwise normal beta-chain. The formula may be written (alpha2)beta(2)(23val-0). The abnormal hemoglobin is present with hemoglobin A in the proposita and in two of her three living children, but is not detectable in her parents. We postulate that this variant represents a triplet base deletion which most likely resulted from an unequal crossing-over between two normal betachain loci during meiosis in one of the parents of the proposita.

Hemoglobin Sphakiá: a delta-chain variant of hemoglobin A2 from Crete.

A new variant of the normal minor component Hb A(2) has been detected in a family that lives in Sphakiá, Crete. Chemical studies of this abnormal hemoglobin, designated Hb A(2) delta Sphakiá, indicates a substitution of the histidyl residue number two of the delta-chain by an arginyl residue.

Phytohemagglutinin-induced lymphocyte transformation in humans receiving delta9-tetrahydrocannabinol.

Eight otherwise healthy male chronic marijuana smokers were hospitalized for a period of 30 days. Initially they received placebo, then a sustained dose of 210 milligrams of delta9-tetrahydrocannabinol (delta9-THC) per day for 18 days, followed by placebo. Lymphocyte responses to phytohemagglutinin were examined during each of these periods. Neither the daily ingestion of marijuana extract containing 210 milligrams of delta9-THC for 18 days nor the history of chronic marijuana smoking had a depressive effect on the lymphocyte responses of these subjects to phytohemagglutinin.

Ontogeny of soluble and mitochondrial tyrosine aminotransferases.

The development of the soluble and mitochondrial forms of tyrosine aminotransferase was observed in fetal and neonatal rhesus monkey tissues. The mitochondrial activity is detectable in early fetal life; the soluble form reaches significant activity just before the birth of the animal.

Heavy metal pollution and co-selection for antibiotic resistance: A microbial palaeontology approach.

Frequent and persistent heavy metal pollution has profound effects on the composition and activity of microbial communities. Heavy metals select for metal resistance but can also co-select for resistance to antibiotics, which is a global health concern. We here document metal concentration, metal resistance and antibiotic resistance along a sediment archive from a pond in the North West of the United Kingdom covering over a century of anthropogenic pollution. We specifically focus on zinc, as it is a ubiquitous and toxic metal contaminant known to co-select for antibiotic resistance, to assess the impact of temporal variation in heavy metal pollution on microbial community diversity and to quantify the selection effects of differential heavy metal exposure on antibiotic resistance. Zinc concentration and bioavailability was found to vary over the core, likely reflecting increased industrialisation around the middle of the 20th century. Zinc concentration had a significant effect on bacterial community composition, as revealed by a positive correlation between the level of zinc tolerance in culturable bacteria and zinc concentration. The proportion of zinc resistant isolates was also positively correlated with resistance to three clinically relevant antibiotics (oxacillin, cefotaxime and trimethoprim). The abundance of the class 1 integron-integrase gene, intI1, marker for anthropogenic pollutants correlated with the prevalence of zinc- and cefotaxime resistance but not with oxacillin and trimethoprim resistance. Our microbial palaeontology approach reveals that metal-contaminated sediments from depths that pre-date the use of antibiotics were enriched in antibiotic resistant bacteria, demonstrating the pervasive effects of metal-antibiotic co-selection in the environment.

Red cell age-related changes of hemoglobins AIa+b and AIc in normal and diabetic subjects.

The minor hemoglobin components, hemoglobin AIa+b and hemoglobin AIc, were measured in the 10% youngest and 10% oldest erythrocytes of 15 normal and 14 diabetic subjects. Erythrocyte fractions were obtained by centrifugation in isopyknic concentrations of dextran: 28.5% of 40,000-mol wt dextran yeilded the 10% lightest of young cells, and 30.5% dextran provided the 10% heaviest or old erythrocytes. Both normal and diabetic erythrocytes contain increased amounts of Hb AIa+b and Hb AIc in old as compared to young cells. In normal subjects, young cells contained 1.2+/-0.2%, and old cells contained 1.8+/-0.4% Hb AIa+b. Corresponding values for diabetic cells were 1.7+/-0.6 and 2.6+/-0.9%. Hb AIc increased from 3.1+/-0.8 to 6.0+/-1.1% in normals and from 5.1+/-2.1 to 10.1+/-3.7% in diabetics. The results indicate that both cell age and diabetes are significant determinants of the amounts of Hb AIa+b and Hb AIc.

Hemoglobin Yakina. I. Clinical and biochemical studies.

Three members of a family who have erythrocytosis and a new hemoglobin, designated hemoglobin Yakima, are described. The abnormal hemoglobin is characterized by the substitution of histidine for aspartic acid at residue 99 in the beta-chain. Of three possible structure-function relations which would account for the increased oxygen affinity of hemoglobin Yakima, only two seem likely. These are: (a) an intrachain shift in the normal relations between the F and G helices and the heme group, or (b) an effect of the substituted side chain at a region of contact between nonpolar residues of the alpha- and beta-chains which favors the oxyhemoglobin quarternary structure.

Differential expression of ryanodine receptors in the rat cochlea.

This study examined the localization and functional expression of ryanodine receptors (RyR) within the cochlea using a combination of reverse transcription-polymerase chain reaction, immunolabeling techniques, and confocal Ca2+ imaging. All three RyR isoform mRNA transcripts were detected in the adult rat cochlea. Immunoperoxidase and immunofluorescence labeling showed that the three isoforms were differentially expressed. The most pronounced RyR protein expression, involving all three isoforms, occurred in the cell bodies of the spiral ganglion neurons. RyR3 labeling extended to the synaptic terminals innervating the inner and outer hair cells. RyR2 expression also occurred in the inner hair cells and supporting cells of the organ of Corti, while cells associated with ion homeostasis in the cochlea, such as the interdental cells of the spiral limbus (RyR1), and the epithelial cells of the spiral prominence and basal cells of the stria vascularis (RyR2 and RyR3), were also immunopositive. The functionality of RyR-gated Ca2+ stores in the spiral ganglion neurons was shown by confocal calcium imaging of fluo-4 fluorescence in rat cochlear slices. Caffeine (5 mM) evoked an increase in intracellular Ca2+ concentration in the cell bodies of the spiral ganglion neurons which occurred inthe absence of external Ca2+. Ryanodine (50 nm-1 microM) evoked comparable increases in intracellular Ca2+ concentration. These findings suggest that RyR-mediated Ca2+ release may be involved in auditory neurotransmission, sound transduction, and cochlear electrochemical homeostasis.

Induction and properties of aryl hydrocarbon hydroxylase in bovine pancreatic ducts.

Inducibility and characteristics of aryl hydrocarbon hydroxylase (AHH) in cultured bovine pancreatic ducts were studied by the fluorometric method. AHH was present and inducible in all the pancreatic ducts studied when they were exposed to 20 microgram benz[a]anthracene (BA)/ml medium. AHH activity in the control tissue ranged from 1.0 to 3.0 U/mg DNA, whereas the activity in the BA-treated tissue was 4.2--28.5 U/mg DNA, which resulted in the induction of 5- to 18-fold activity. At 12 hours of BA exposure, AHH activity in the treated tissue was 12-fold that in the control tissue and continued to increase to 15-, 19-, and 31-fold that in the control tissue at 24, 48, and 72 hours, respectively. The BA-induced AHH activity had a broad pH optimum between 7.1 and 7.7, and the maximum activity was found at pH 7.4. The AHH activity was linear with respect to the incubation time up to 30 minutes. The effect of the benzo[a]pyrene concentration on AHH activity was studied on the BA-induced enzyme. The apparent Michaelis constant for the substrate was 0.5 microM, and the maximum velocity was 8.6 U/mg DNA. BA-induced AHH activity was inhibited 65% by 100 microM 7,8-benzoflavone, whereas the control enzyme activity was stimulated 100% by the same concentration of 7,8-benzoflavone.

Carcinogenesis in the pancreas. I. Long-term explant culture of human and bovine pancreatic ducts.

Bovine and human pancreatic ductal explants were maintained in long-term culture. Bovine ducts were cultured for 85 days, whereas human ducts have been cultured for up to 60 days. The explants all maintained good ultrastructural preservation for these periods and also incorporated radioactive precursors into protein, RNA, and DNA. Uncultured ducts, which were fixed for electron micrsoscopic study, demonstrated classical signs of reversible cell injury (dilated endoplasmic reticulum and swollen mitochondria), and cultured explants did not. However, the cultured tissues did show sublethal alterations such as the formation of numerous autophagic vacuoles and residual bodies and the accumulation of large lipid droplets. This study demonstrated the feasibility of maintaining pancreatic ducts in long-term explant culture, which enables them to be used in experimental studies involving chemical carcinogens and in structural and functional studies.

Long-term survival of normal adult human tissues as xenografts in congenitally athymic nude mice.

Bronchi, pancreatic ducts, and colons from adult human were maintained as xenografts in congenitally athymic nude N:NIH(S) mice for 715, 145, and 89 days, respectively. After an ischemic crisis and revascularization of the human tissue, the epithelium regenerated to a normal differentiated morphology. The long-term survival of normal adult human epithelial tissues as xenografts provides model systems for the study of the interactions of chemical and/or physical carcinogens with human tissues.

Cancer-associated alterations of blood group antigen expression in the human pancreas.

Certain alterations of blood group substance (BGS) expression have been observed in gastrointestinal cancer tissues. However, in the pancreas little is known about BGS expression by normal or malignant tissue. The present immunohistochemical study analyzed simultaneously the expression of A, B, H, Lewisa (Lea), and Lewisb (Leb) antigens in specimens of normal pancreas, chronic pancreatitis, and pancreatic carcinoma (primary and metastatic). In normal pancreas all five antigens were expressed in ducts, ductules, and acini, but not in islets. Acinar cells expressed A, B, H, and Leb in supranuclear cytoplasm, whereas Lea was found mainly on centroacinar cells. Only BGSs that were appropriate for the host's blood type were expressed, except for one case of Lea deletion. BGS expression by chronic pancreatitis tissue closely resembled that by normal tissue. In primary pancreatic cancer two cancer-associated alterations were noted that were not found in either normal pancreas or chronic pancreatitis. Deletion of an expected A, B, H, or Leb antigen occurred in approximately 25% of cases, particularly in more poorly differentiated cancers. Incompatible expression of an unexpected A or B antigen occurred in 33% of cases, regardless of degree of differentiation. Metastatic pancreatic cancers also exhibited BGS deletion and incompatibility. In both primary and metastatic cancers the incidence of incompatible A or B expression was higher in cancers from the United States than in cancers from Japan, but the incidence of BGS deletion was similar between the two countries. It was concluded that deletion of A, B, H, or Leb antigens and incompatible expression of A or B antigens are cancer-associated events in the pancreas.

Human bronchial epithelial cells transformed by the c-raf-1 and c-myc protooncogenes induce multidifferentiated carcinomas in nude mice: a model for lung carcinogenesis.

We have previously described the neoplastic transformation of immortalized human bronchial epithelial cells (BEAS-2B) by the combination of the c-raf-1 and c-myc protooncogenes and the concomitant induction of neuron-specific enolase mRNA expression (A. Pfeifer et al., Proc. Natl. Acad. Sci. USA, 86: 10075-10079, 1989). In this paper we describe the morphological, biochemical, and immunohistochemical characteristics of the primary c-raf-1/c-myc tumors, xenografts of these tumors, and tumors that originated from cell lines of the primary neoplasm. The tumors were morphologically characterized by the appearance of desmosomes and tonofilaments, microvilli, and dense core granules representing markers of squamous, glandular, and neuroendocrine differentiation, respectively. A total of 11 of 13 tumors were positive by immunohistochemical techniques for neuron-specific enolase, serotonin (nine of 13), and calcitonin (six of 13). Keratins were expressed in 11 of 13 tumors, and while specific keratins (K5, K7, K16/K17) decreased, there was an increase of vimentin in the tumor cells. Gastrin-releasing peptide immunoreactivity was detectable in a small number of tumors (five of 13). BEAS-2B cells transfected with the c-raf-1 and c-myc protooncogenes and cell lines established from the primary tumors expressed major histocompatibility Class II antigen which has been found on small cell lung carcinoma cells. The tumors induced by the c-raf-1 and c-myc protooncogenes resemble the multidifferentiated phenotype of small cell lung cancer frequently detected in vivo and present a defined model to study the relation between molecular markers, phenotypical appearance, and response to chemotherapeutic agents and radiation.

p53 protein accumulates frequently in early bronchial neoplasia.

p53 mutations are common in human lung cancer and frequently generate levels of p53 protein that are detectable by immunohistochemistry. For this reason, p53 protein accumulation is a candidate biomarker, but little is known about its timing or frequency in multistage bronchial carcinogenesis. We studied human lung tissues containing preinvasive squamous neoplasms from 34 donors with and without lung cancer. Nuclear p53 protein was present in 0% of normal mucosas, 6.7% of squamous metaplasias, 29.5% of mild dysplasias, 26.9% of moderate dysplasias, 59.7% of severe dysplasias, 58.5% of carcinomas in situ, 67.5% of microinvasive carcinomas, and 79.5% of invasive tumors. These data indicate that (a) p53 protein accumulates in about 30% of the earliest recognized neoplastic lesions (i.e., mild dysplasia), (b) there is an increasing frequency of p53 protein accumulation starting with mild dysplasia, and (c) p53 protein accumulates infrequently in normal or metaplastic mucosa. In a subset of six patients whose most advanced lesion was carcinoma in situ without evidence of invasive cancer, p53 protein was detected in 0% of normal mucosas, 8.3% of squamous metaplasias, 37.5% of mild dysplasias, 12.5% of moderate dysplasias, 93.8% of severe dysplasias, and 55% of carcinoma in situ lesions. These data show clearly that p53 alterations can occur before invasion and suggest that the frequency is similar to that observed in the full series. Since two-thirds or more of lung cancers have p53 alterations, the timing and frequency of p53 protein accumulation make the p53 tumor suppressor gene an attractive marker for early diagnosis and evaluation of chemoprevention agents.

Two new hemoglobins. Hemoglobin Alabama (beta39(C5)Gln leads to Lys) and hemoglobin Montgomery (alpha 48(CD 6) Leu leads to Arg).

The amino acid substitutions in two new hemoglobins found by electrophoretic screening during a survey in Alabama have been determined by column chromatography and amino acid analyses of their tryptic peptides. They are hemoglobin Alabama (beta 39(C 5)Gln leads to Lys) and hemoglobin Montgomery (alpha 48(CD 6) Leu leads to Arg). No harmful symptoms have been attributed to the presence of either hemoglobin.

Role of Bohr group salt bridges in cooperativity in hemoglobin.

Possible problems in measuring the first Adair constant, K1, from accurate oxygen equilibrium curves have been investigated. Of these only the presence of small amounts of CO-hemoglobin or hemoglobin dimers had a significant effect. The former can be eliminated by treatment with oxygen, the latter by measuring the concentration-dependence of K1 or working at high protein concentrations. K1 values have been measured for normal hemoglobin at pH 7 and 9, hemoglobin specifically reacted with cyanate at Val 1alpha (alphac2beta2) and des(His 146beta) hemoglobin at pH 7. K1 is equal to KT, the oxygen affinity of the T state of hemoglobin, for all these hemoglobins and was increased in all of them when compared to normal hemoglobin at pH 7. This shows that the breakage of the Bohr group salt bridges by increasing pH or specific modification changes KT. Hence the Bohr group salt bridges break on ligation of the T state and are partially responsible for the free energy of cooperativity.

Haemoglobin F Victoria Jubilee (alpha 2 A gamma 2 80 Asp-Try).

A new A gamma chain haemoglobin variant, haemoglobin F Victoria Jubilee, with an electrophoretic mobility slightly anodal to haemoglobin F Port Royal, was found in a Jamaican infant. The amino acid residue substitution of 80 Aspartic Acid leads to Tyrosine was associated with alanine in position 136. Haemoglobin F Victoria Jubilee constituted about 7.0 percent of the total haemoglobin F.